Spray-On Batteries: A Breakthrough in Battery Design and Integration

Researchers have recently reported the development of a spray-on lithium ion battery that can be painted on various surfaces, effectively converting any object into a possible energy storage device. The implications of this technology in solar energy applications are staggering as we imagine buildings and massive infrastructures doubling as solar batteries. It would mean an end to the energy crisis and a new era of green technology where solar energy supplies all global energy needs.

Neelam Singh leads a team of researchers working in Rice University and Catholic University of Louvain in developing this new technology. Singh said the current direction in battery design is integration of batteries into various objects like textiles.

Singh’s group came up with a spray-on lithium ion battery that can be aerosol painted in five layers. These layers comprise a positive current collector, a cathode to attract positively charged ions, an ion-conducting separator, an anode to attract negatively charged ions, and a negative current collector.

This spray-on battery design was tested on various surfaces like ceramic tiles, glass, flexible transparency film and stainless steel. All the tests gave positive results. In one test, a solar cell was hooked to a painted battery and it was able to successfully power an LED display.

Singh reported that their group is currently working on ways to fabricate a stable and powerful battery using this new design. The main difficulty is finding ways to get the battery layers on top of each other without disrupting one another’s capacity and affecting the overall battery performance.

Another challenge is the replacement of aluminum that is traditionally used as a positive current collector in lithium ion battery. Since aluminum is a lung irritant, it would be hazardous to use aluminum in aerosol applications.

In order to promote safety, the research team replaced aluminum with carbon nanotubes as a positive current collector. Lithium cobalt oxide was used as a cathode, commercial gel electrolyte as a separator, lithium titanium oxide as an anode, and copper as a negative current collector.

Future challenges for the new battery design is to make it stable in contact with air and moisture. Currently, the electrolyte separator is reactive and explodes in contact with oxygen. Hence, special conditions must be observed in the application of this technology.

Singh reported that their research group is looking into various materials to make spray-on battery more environmentally friendly and less reactive to air and moisture. Another direction for their group is painted solar batteries, in tandem with another group’s research on paint-on solar cells. Future implications for these new technologies are houses doubling as solar energy capture and storage devices.

Read more about their research in the June 28 issue of Scientific Reports.